1. Field of the Invention
The present invention relates to a method and a device for identifying a set of pixels, the values of which are intended to be used to determine the value of a target pixel.
The present invention is, for example but not limitingly, applicable in processing systems for the purpose of eliminating the noise present in digital images or in processing systems for the purpose of enhancing the contours in digital images.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Conventionally, in digital image processing, the values of the pixels of the digital images are determined according to the values of the pixels neighboring the processed pixel. These determinations are conventionally carried out using pixel convolution products. The purpose of these processing operations is to provide an image with less noise, while still preserving the other characteristics of the image.
In practice, noise reduction is generally accompanied by a partial reduction in the textures and/or by a substantial diffusing of the edges or contours and of the salient points within the digital image.
Certain processing methods use what are called “anisotropic” convolutions: a set of neighbouring pixels is determined for each pixel as a function of the values taken by the neighbouring pixels. Such approaches locally adapt the set of pixels used for determining the value of a pixel in order to take into account the characteristics of the processed image. These methods are expensive in terms of computing time and the processing time for small images is typically measured in seconds.
Although useful as regards quality of the image processing, these methods are not suitable for real-time processing of video sequences.